Rapid Intrathecal Fluorescein Injection During Cerebrospinal Fluid Leak Repair Is Safe and Effective

ABSTRACT Objective Intrathecal fluorescein (IF) is effective for localizing nasal cerebrospinal fluid (CSF) leaks along the skull base during endoscopic exploration, with largest studies reporting sensitivities ranging from 66%–93%. Due to reports of intraoperative and postoperative neurologic complications such as seizures and paralysis, surgeons often dilute the fluorescein and inject it intrathecally slowly over a variable amount of time. However, no study has assessed whether rapid IF administration causes the aforementioned risks or whether it affects its accuracy in identifying CSF leaks intraoperatively. Methods A prospective study was conducted from 2015 to 2024, where all patients undergoing endoscopic exploration and/or repair of CSF rhinorrhea had 0.1 mL of 10% fluorescein (10 mg) mixed with 3–5 mL of patients' CSF injected rapidly via the lumbar drain over a few seconds. Results Of the 82 included patients, the mean age was 53.8 ± 15.2 years, and 84% were female. Sixty‐nine patients underwent successful endoscopic CSF leak repairs, and 13 had negative endoscopic explorations. Rapid IF injection was 80% sensitive (20% false negative rate) and 100% specific for identifying CSF leaks, and it caused no seizures, paralysis, or other neurologic complications. Conclusion Compared to prior reports of slow low‐dose IF injection for CSF leak localization, rapid IF injection yielded similar efficacy (80% sensitivity) with no IF‐related complications. Rapid IF injection was safe and effective but should be corroborated by future studies. Level of Evidence 4.